1. Field of the Invention
The present invention relates to a universal timepiece from which a latitude and a longitude can be determined and more particularly, to a universal timepiece from which a latitude, a longitude and the present time can be correctly appreciated even at unknown place.
2. Description of the Prior Art
According to circumstances, there""s a moment when you should appreciate a position and the present time at that position only with a timepiece and without any special measuring tools. For example, when one meets a shipwreck on a vast expanse of water or one fells behind in a back region, can be illustrated. At this time, measuring methods of the position and the time is known as follows. However, one should memorize a correct difference between the region where his timepiece has been adjusted and the Greenwich mean time for the application of this method.
First, a simple protractor is made for measuring the angles of 45 and 22.5, and the angle between the horizontal line from the present position and the Polaris, that is, the altitude of the Polaris, is measured using the protractor. If the position is southern hemisphere, the altitude of a star representing the south pole of the celestial sphere, is measured. The altitude of the Polaris coincides with the north latitude at that place and the altitude of the south pole of the celestial sphere coincides with the south latitude at that place. Therefore, the latitude at that position can be determined.
Next, the sunrise time and the sunset time are measured for determining the length of day and determining the culmination time of the sun by adding the half of the length of the day to the sunrise time. Then, the culmination time of the sun at that position is transformed to the Greenwich mean time and then subtract 12 from the transformed value. Through crossing thus obtained time value with 15 /hour, the longitude at the position can be obtained.
According to the above-mentioned method, the latitude, the longitude and the present time can be determined by using a common timepiece. However, it is difficult to utilize this method because of the following reasons. One should remember correctly the time difference between the time where the timepiece has been adjusted and the Greenwich mean time. And the altitude of the Polaris should be measured correctly. In addition, the calculation is very complicated. Therefore, this method is rarely utilized in case of emergency.
Accordingly, it is an object of the present invention to solve the problems of the conventional method and providing a universal timepiece of which possession is advantageous and from which the latitude, the longitude and the present time at an unknown place, can be immediately appreciated without any additional operation or complicated calculation.
To accomplish the above-mentioned object, there is provided in the present invention a timepiece having a star plate for measuring the latitude and the longitude during night.
There also is provided in the present invention a timepiece having a measuring bar or a measuring hole for measuring the longitude during day.